A large number of people, including those suffering from conditions such as diabetes, use some form of infusion therapy, such as daily insulin infusions, to maintain close control of their glucose levels. Currently, there are two principal modes of daily insulin therapy. The first mode includes syringes and insulin pens. These devices are simple to use and are relatively low in cost, but they require a needle stick at each injection, typically three to four times per day. The second mode includes infusion pump therapy, which entails the purchase of an insulin pump that lasts for about three years. The initial cost of the pump can be significant, but from a user perspective, the overwhelming majority of patients who have used pumps prefer to remain with pumps for the rest of their lives. Infusion pumps, although more complex than syringes and pens, offer the advantages of continuous infusion of insulin, precision dosing and programmable delivery schedules. This results in closer blood glucose control and an improved feeling of wellness.
The use of an infusion pump further requires the use of a disposable component, typically referred to as an infusion set or pump set, which conveys the insulin from a reservoir within the pump into the skin of the user. An infusion set typically consists of a pump connector, a length of tubing, and a hub or base from which an infusion needle or cannula extends. The hub or base has an adhesive that retains the base on the skin surface during use. The hub or base may be applied to the skin manually or with the aid of a manual or automatic insertion device. Often, the insertion device is a separate, stand-alone unit that the user is required to carry and provide.
There are many available versions of infusion sets, including steel cannula infusion sets and soft (flexible) catheter sets. Soft catheter sets are typically inserted into a patient manually with the aid of a steel introducer needle, which is later removed from the patient leaving the soft catheter in place. In another type of infusion set, as noted above, a mechanized inserter is used to insert the introducer needle and catheter, remove the introducer needle, or both. The introducer needle is completely removed from the infusion set before being connected to the insulin pump.
One problem associated with manually inserting and retracting the introducer needle is variability in the insertion and retraction force, speed, smoothness and angle. This variability can lead to an increased rate of catheter insertion failure.
Further, as noted above, the user typically must remove the introducer needle after inserting the cannula. This exposes the user to accidental needle sticks from handling the removed introducer needle.
Accordingly, a need exists for an infusion set that facilitates insertion of the cannula, while reducing the number of components a user must carry and substantially preventing accidental introducer needle sticks.